The invention relates to a lock cylinder comprising an external housing which accommodates, on its rear face, a closure element acting upon a mortise lock or the like and an exchangeably inserted core unit, the casing of which contains housing pins as tumblers and a cylinder core equipped with a key channel, the cylinder core also receiving core pins as tumblers and being connected in a plug-in manner to coupling pins which issue from the closure element and project freely into a socket in the external housing, serving for insertion of the core unit.
The sockets produced as blind holes for the coupling pins arranged in pairs extend in the region of the greatest accumulation of material on both sides of the key channel and end just behind the visible side of the cylinder core. If the coupling pins are of equal lengths, this not only involves unnecessarily deep engagement with the cylinder core but also occupies a region which is better suited to the closure and tumbler variations. The security, on both sides of the key channel is thus increased unnecessarily regardless of the increased production costs.
It is an object of the present invention to construct a lock cylinder of this type which is simple to produce and is sturdy in use so that, as far as possible more space also remains transverse to the key channel in the cylinder core while maintaining the advantages of the plug-in connection with the closure element.